NEW YORK - Pfizer Inc. on Friday said its popular Celebrex arthritis drug more than doubled the risk of heart attack in a large cancer-prevention trial, a setback that comes just weeks after Merck & Co. recalled its similar Vioxx drug due to heart safety risks.
Shortly after the Celebrex news, the New England Journal of Medicine carried a letter in which Vanderbilt University cardiologists questioned the safety of Pfizer's newer arthritis drug, Bextra, and recommended doctors not prescribe it.
Shares of Pfizer, a component of the Dow Jones industrial average, fell 11.1 percent following the double blast of bad news.
Merck recalled Vioxx on Sept. 30 after a study found that long-term use of the drug doubled the risk of heart attack and stroke. Both Celebrex and Vioxx belong to a class of drugs known as COX-2 inhibitors, as does Bextra.
"It is now a fair question to ask whether Celebrex and Bextra could be removed from the market," Prudential Equity Group analyst Tim Anderson said in a research report.
Some analysts have estimated Merck faces tens of billions of dollars in potential future liability claims from former users of Vioxx. Anderson said Pfizer must be concerned about its own legal risk if Celebrex and Bextra remain on the market.
"This does not bode well for COX-2 inhibitors in general," Ira Loss, an analyst at Washington Analysis, said of the Celebrex trial. "The sense had been that Celebrex is somehow different from the others."
Dr. Richard Hayes, a cardiologist at New York University, told Reuters, "This raises my concern about Celebrex and all the COX-2 inhibitors, so I will no longer be prescribing any of them."
A Pfizer spokesman said the company has no plans to pull Celebrex off the market. It is one of the drugmaker's biggest products, with 2003 sales of $1.9 billion. Bextra had sales last year of $687 million.
The U.S. Food and Drug Administration said it was reviewing the new Celebrex data and will determine "appropriate action." Meanwhile, it urged doctors to consider alternative treatments.
Pfizer shed almost $24 billion in market capitalization, its stock closing down $3.23 to $25.75 on the New York Stock Exchange and dragging down the Dow Jones industrial average as well as other pharmaceutical stocks. Pfizer is off almost 30 percent this year.
MORE TROUBLE FOR COX-2s
Pfizer said the Celebrex trial, sponsored by the National Cancer Institute, involved patients taking 400-milligram and 800-milligram daily doses of the drug to prevent tumors known as adenomas that grow from glandular tissue. High doses of the anti-inflammatory drug were being tested on the theory that inflammation is a cause of cancer.
Vioxx and Celebrex both work by selectively blocking a protein called COX-2 that has been linked to inflammation. They were both launched in 1999 and quickly became top-selling drugs, helped by massive television and print advertising.
Pfizer also said on Friday that Celebrex was not shown to increase heart risk in a second long-term trial designed to see if the drug could prevent colon polyps. Negative findings in a similar trial led to the withdrawal of Vioxx.
New York-based Pfizer said National Cancer Institute officials decided to halt the Celebrex trial on adenomas after confirming "an approximately 2.5-fold increase" in the risk of fatal or non-fatal heart attack in patients taking the drug, compared with patients taking a placebo.
Pfizer Chief Executive Officer Hank McKinnell on Friday told CNBC television he does not believe the continuing negative news on COX-2 drugs, including Celebrex and Bextra, will spell their eventual demise.
"I don't believe they're doomed," he said, arguing that older standard painkillers cause ulcers and gastrointestinal bleeding that kill 16,500 Americans each year and that the COX-2 pills are gentler on the stomach.
Amid concerns about the safety of all COX-2 inhibitors after the Vioxx withdrawal, Pfizer plans to begin a major new trial next year to verify the heart-safety of Celebrex in arthritis patients who have had a recent heart attack.
The company has also defended Bextra's safety, although Pfizer's newer treatment raised the risk of stroke and heart attack in two small clinical trials of patients taking it after coronary bypass surgery.
In other fallout from the Celebrex news, Moody's Investors Service on Friday said it revised Pfizer Inc.'s outlook to negative from stable but affirmed its long-term debt ratings.
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